Uric acid

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Version / remarks:

The present study was conducted according to:
OECD, 2004 : The Organisation for Economic Co-operation and Development (OECD) Guidelines for the Testing of Chemicals, OECD 202, Daphnia sp., Acute Immobilisation Test, adopted by the Council on April 13, 2004.

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

10 mL of test samples from each replicates were drawn and mixed together for each group at 0 and 48 h. The samples were divided into two equal portions. One portion (20 mL) was sent for test concentration analysis and the second portion (20 mL) was stored at -20 ± 5 ºC temperature till the study completion. Active ingredient concentration in water was determined using the validated analytical method.

Vehicle:

no

Details on test solutions:

A quantity of 60 mg uric acid was transferred in 2000 mL beaker and volume was made up to 1000 mL with reconstituted water and sonicated for 1 h to obtain the nominal concentration of 0.06 mg/mL (stock A). Volume of 99.5 mL was taken from the stock A, transferred using a pipette in glass beakers of 600 mL capacity to obtain the nominal test concentration of 60.0 mg uric acid/L.

Test organisms (species):

Daphnia magna

Details on test organisms:

Healthy Daphnia magna (showing no signs of stress such as presence of males and ephippia, delay in the production of the first brood, discolouration, etc. and having normal behavior) less than 24 h old (first instar nymph) cultured and bred in the Laboratory of Ecotoxicology, Jai Research Foundation, were used for the study. The master culture of Daphnia magna was originally procured from the MicroBio Test Inc, Kleimoer 15, 9030 Mariakerke (Gent), Belgium. The test system was validated for its sensitivity by conducting a validation study (Patel, D.K., 2018: JRF Study N° 502-3-07-19120) with potassium dichromate as a positive control.

Test type:

static

Water media type:

other: Reconstituted water was prepared by adding different chemicals to the distilled water

Total exposure duration:

48 h

Remarks on exposure duration:

All test daphnids were observed for immobility and abnormal behaviour or appearance, at 0, 24, and 48 h of exposure..

Post exposure observation period:

no

Hardness:

hardness (184.8 mg/L as CaCO3)

Test temperature:

between 20.2 and 21.3 °C

pH:

7.11 and 7.67

Dissolved oxygen:

8.10 and 8.39 mg/L

Salinity:

na

Conductivity:

na

Nominal and measured concentrations:

Nominal concentration is 60 mg/L., at 48h 59.18660 mg/L is the measured concentration.

Details on test conditions:

Temperature, pH, and dissolved oxygen content (using Multi portable meter) of reconstituted water were recorded at 0 and 48 h. Total hardness of reconstituted water was measured once during acclimatisation and test period using the titrimetric method (IS 3025, 1983). The pH did not vary by more than 1.5 units in any of the tests. Temperature, dissolved oxygen, and total hardness were within the guideline limits.
The whole study was conducted in a specially designed low temperature water bath preset to a water temperature of 20.0 °C (constant within ± 1°C). Uniform temperature in the water chamber of the water bath was obtained by maintaining a slow flow of water by a motor. The beakers containing the test solutions with daphnids were kept in the water bath. The beakers were held in position by special clamps provided within the chamber of the water bath.
A photoperiod of 16 h light and 8 h darkness cycle was maintained with an automatic timer attached to the water bath. Lighting was provided via fluorescent tubes attached on the lid of the low temperature water bath.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 60 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

EC50 (24 and 48 h), NOEC and LOEC: Greater than the test concentration of 60.0 mg uric acid/L.

Results with reference substance (positive control):

valid

Reported statistics and error estimates:

na

Validity criteria fulfilled:

yes

Conclusions:

EC50(24 and 48 h), NOEC and LOEC:  Greater than the test concentration of 60.0 mg uric acid/L.

Executive summary:

No immobilisation was observed at the test concentration of 60.0 mg uric acid/L as well as in the control (without uric acid) at 24 and 48 h. Daphnids exposed to 60.0 mg uric acid/L and control (without uric acid) did not exhibit any abnormal behavioural symptoms at 24 and 48 h.

EC₅₀(24 and 48 h), NOEC and LOEC:  Greater than the test concentration of 60.0 mg uric acid/L.

Control immobilisation was 0% (not exceed 10%) at the termination, thus the validity criterion was met.

Dissolved oxygen concentration was ≥ 8.10 mg/L in the control and test vessels at the end of the test thus the validity criterion was met.

Daphnia in the control groups did not show immobilisation or other signs or disease or stress e.g. discoloration or unusual behavior such as trapping at the surface of water.

Description of key information

EC₅₀(24 and 48 h), NOEC and LOEC:  Greater than the test concentration of 60.0 mg uric acid/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

60 mg/L